dovecot - Jun 2014 - Any issues with dsync between 2.1.7 and 2.2.9 ?

My current production system is running dovecot 2.1.7-7ubuntu1 on
Ubuntu 13.04, and I'm building a new setup based on Ubuntu 14.04 with
dovecot 2.2.9-1ubuntu2.1 - current standard in the repos. I'd like to
use replication to get the mailstore from the old system to the new. Are
there any caveats or gotchas to be aware of ? 

Is it possible to make
it a one-way replication ? So problems or glitches on the new setup
don't propagate to the old production ? 

Thanks - 

D.